Space limitations often prevent the use of portable pressurized containers such as pressurized aerosol cans at the workstation point where the pressurized container contents are required. For example, in removing dust particles from cameras, projectors and optical lenses, in cleaning film gates, tape recording heads and tape deck rollers and reels, in cleaning intricate internal parts of electric motors, switch mechanisms and other electrical components, in cleaning the type bars of typewriters or in removing dust and foreign particles from intricate mechanisms such as sewing machines, gear trains and other minute precision assemblies, the manipulation of a pressurized container of solvent or compressed gaseous cleaning agents is often impossible.
In addition, the weight and awkwardness of manually holding a pressurized container such as an aerosol can for long periods of time often proves fatiguing to those engaged in close delicate work.
For these reasons there is a need for practical and convenient pressurized containers providing remote delivery of the container contents.
In such remote delivery systems, local manual control at the remote delivery station is required to avoid wasting the pressurized gas, and an overriding "arming" and "disarming" control is required at the pressurized container to avoid the loss of escaping pressurized gas from the flexible conduit or the connecting fittings, which are thereby relieved of internal pressure loads except when remote delivery operations are required.
Several devices have been proposed to provide this dual release valve capability. U.S. Pat. No. 3,410,492 and 3,428,224 both show complex and expensive, multiple-part, container valve actuating mechanisms providing the desired overriding shut-off control of the pressurized fluid at the pressurized container itself. These complex and expensive devices are not well adapted for cooperation with conventional aerosol cans, and they involve serious risk of leakage losses of pressurized contents.
Another remote delivery nozzle system is disclosed in U.S. Pat. No. 3,650,438 assigned to the same assignee as the present application, the disclosure of which patent is hereby incorporated by reference. The remote delivery nozzle system disclosed in such prior patent comprises a pressure control assembly mounted on the top of the pressurized container and also includes an eccentric connector coupling the valve stem of the container to an elongate flexible tube employed to deliver the pressurized contents to a remote release nozzle. An eccentrically-apertured rotatable container cap cooperates with the eccentric connector to tilt the valve stem of the container when the cap is rotated thereby supplying "arming" pressure from the container through the flexible conduit to the manually actuated remote release nozzle.
The remote nozzle is formed as an elongated, hollow wand-like device having an internal bore communicating at the end of the nozzle with a release valve. The valve is a tiltable aerosol-can type release valve employing an inverted mushroom-shaped valve stem having an enlarged underlying flange upturned around its edge and maintained in sealing contact with the underside of an elastomer washer by a helical coil spring compressed between the flange and an internal shelf formed within the bore inside the nozzle. Depression or tilting of the release valve separates the flange from the elastomer washer by deforming the resilient spring, thereby connecting the bore within the nozzle through a lateral metering orifice to the delivery bore of the release valve. When the internal bore of the remote release nozzle is supplied with pressurized gas, actuation of the valve releases this pressurized gas for delivery through a delivery orifice.
A length of flexible tubing sealingly joined to the lower end of the bore of the release nozzle connects the release nozzle with the pressurized container, such as an aerosol can. The tubing extends through the eccentric aperture formed in the upper portion of the rotatable cap.
While this prior art remote delivery nozzle assembly is satisfactory in most respects, it is subject to several serious objections. For example, the eccentric connector and valve cap require precise alignment in order to operate properly and are not entirely suitable for use with those types of pressurized cans having a valve stem assembly which requires substantial downward movement, rather than merely tilting thereof, in order to allow escape of the pressurized contents through the valve stem. More significantly, because the eccentric connector extends through an eccentric aperture in the valve cap, minor leakage of the pressurized contents between the valve stem of the container and the eccentric connector sometimes occurs which results in escape of the contents through the aperture in the cap, thereby wasting the contents. Also, because the user is required to fit the eccentric connector onto the valve stem of the container prior to fitting the cap onto the container, the valve stem is often tilted or depressed during the fitting thereof with the eccentric connector, thereby allowing escape of the contents between the valve stem and the eccentric connector, which in some cases is not only wasteful but also contaminates the area adjacent the container.
Further, the tiltable valve on top of the remote delivery nozzle or wand for delivering the pressurized contents of the container at the remote location is not very accurate, causing waste of the pressurized contents. Finger fatigue is also a problem when attempting to hold the valve open for any protracted period of time.
In U.S. patent application Ser. No. 883,551, also assigned to the same assignee as the present application, a remote delivery nozzle assembly for a pressurized container is disclosed which seeks to rectify certain of the deficiencies noted above. This disclosure is also incorporated herein by reference.
According to that invention, a connector element extends through the top of a cylindrically shaped cap which is adapted to frictionally engage the upstanding annular rim on a standard aerosol can type container. The connector element is secured to the cap by means of a friction fit interlock while an O-ring provides sealing engagement between the connector element and the cap to provide a gas-tight enclosure surrounding the valve stem of the container. The connector element includes an elongated bore therethrough into the opposite ends of which the valve stem of the container and a flexible conduit are respectively received. The connector element includes shoulder portions within the bore which sealingly engage the end of the valve stem and urge the latter downwardly to release the pressurized contents when the cap is fitted onto the pressurized container. The connector assembly is installed on the container by merely fitting the cap onto the upstanding rim of the container, thereby eliminating the need for separately aligning and fitting the connector element onto the valve stem before the cap is installed. Once installed on the container, the connector assembly automatically "arms" the remote delivery nozzle. "Disarming" is effected simply by removing the cap from the container.
While the pressure control portion of the remote delivery nozzle assembly constitutes a distinct improvement in "arming" or pressurizing the remote delivery nozzle by simply disposing the cap on the container, the friction fit of the cap on the top rim or lip of the container is not all that satisfactory, since the cap is merely clamped to the outside of the lip by being spread and clampingly engaged to the outer surface. Movement of the container can result in dislodgment of the cap and "disarming" of the remote nozzle. Further, when the cap is voluntarily removed so as to "disarm" the remote nozzle, there is no shield against a spray from the pressurized container, until the container valve is closed. This often results in the user or the surrounding environs being sprayed with a foreign chemical substance.
The invention disclosed in this application, also does not make any improvements in the wand or remote delivery nozzle, which is the same as that disclosed in U.S. Pat. No. 3,650,438.